| //=== PointerArithChecker.cpp - Pointer arithmetic checker -----*- C++ -*--===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This files defines PointerArithChecker, a builtin checker that checks for |
| // pointer arithmetic on locations other than array elements. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Analysis/PathSensitive/CheckerVisitor.h" |
| #include "GRExprEngineInternalChecks.h" |
| |
| using namespace clang; |
| |
| namespace { |
| class PointerArithChecker |
| : public CheckerVisitor<PointerArithChecker> { |
| BuiltinBug *BT; |
| public: |
| PointerArithChecker() : BT(0) {} |
| static void *getTag(); |
| void PreVisitBinaryOperator(CheckerContext &C, const BinaryOperator *B); |
| }; |
| } |
| |
| void *PointerArithChecker::getTag() { |
| static int x; |
| return &x; |
| } |
| |
| void PointerArithChecker::PreVisitBinaryOperator(CheckerContext &C, |
| const BinaryOperator *B) { |
| if (B->getOpcode() != BinaryOperator::Sub && |
| B->getOpcode() != BinaryOperator::Add) |
| return; |
| |
| const GRState *state = C.getState(); |
| SVal LV = state->getSVal(B->getLHS()); |
| SVal RV = state->getSVal(B->getRHS()); |
| |
| const MemRegion *LR = LV.getAsRegion(); |
| |
| if (!LR || !RV.isConstant()) |
| return; |
| |
| // If pointer arithmetic is done on variables of non-array type, this often |
| // means behavior rely on memory organization, which is dangerous. |
| if (isa<VarRegion>(LR) || isa<CodeTextRegion>(LR) || |
| isa<CompoundLiteralRegion>(LR)) { |
| |
| if (ExplodedNode *N = C.GenerateNode()) { |
| if (!BT) |
| BT = new BuiltinBug("Dangerous pointer arithmetic", |
| "Pointer arithmetic done on non-array variables " |
| "means reliance on memory layout, which is " |
| "dangerous."); |
| RangedBugReport *R = new RangedBugReport(*BT, BT->getDescription(), N); |
| R->addRange(B->getSourceRange()); |
| C.EmitReport(R); |
| } |
| } |
| } |
| |
| void clang::RegisterPointerArithChecker(GRExprEngine &Eng) { |
| Eng.registerCheck(new PointerArithChecker()); |
| } |